Fig. 12. The blue cone pathway of the primate retina. Blue cone contacting bipolar cells (BCB) make invaginating contacts with blue cones (BC) in the outer retina. The blue cone bipolar axon terminal provides input to a blue/yellow color coded ganglion cell (B/Y GC) in the inner plexiform layer. The yellow surround is provided by diffuse cone bipolars (FB), which contact both L and M cones at basal junctions. Other cell types: C, cone; R, rod; DFIG and H2, horizontal cells, MB; midget bipolar; RB, rod bipolar; A, amacrine cell; MG, midget ganglion cell; DG, diffuse ganglion cell. (Drawing courtesy of Dr. Helga Kolb, based on Dowling JE, Boycott BB: Organization of the primate retina: Electron microscopy. Proc R Soc Lond Biol 166:80, 1966)